Abstract

Abstract

Breeding efforts to improve whole grain quality of oats (Avena sativa L. and A. byzantina K. Koch) have been limited by difficulties in measuring the trait. In vitro chemical and biological tests have been used to predict grain digestibility, but laboratory facilities are required, and the procedures are time and labor intensive. Consequently, breeders primarily have used grain test weight as a crude measure of grain quality. Our objectives were to determine the relationships among indicators of grain quality, environmental effects, and practical utility of the measurement techniques. Sixteen oat cultivars were grown at two locations during each of 2 yrs on either Typic or Ultic Hapludalf soils. Traits measured were grain yield, test weight, groat fraction, acid detergent fiber (ADF), permanganate lignin, in vitro dry matter disappearance (IVDMD), groat protein, and whole grain protein. Cultivar means for IVDMD ranged from 600 to 758 g kg−1. There were consistent negative correlations and linear relationships between IVDMD and both ADF and lignin. The relationship between IVDMD and groat fraction was linear and r2 values ranged from 0.61 to 0.81, so groat fraction should be a useful indicator of the digestible energy of whole grain oats. Test weight and IVDMD were not correlated when test weights were near normal, but they were correlated when test weights were light. Test weight was not a reliable indicator of genetic variability for whole grain quality. Groat and whole grain protein concentrations are not associated with IVDMD. Whole grain protein concentration was consistently correlated with groat protein, but only 37 to 69% of the variation in whole grain protein was associated with variation in groat protein concentration. Among the indicators of digestible energy, the least amount of labor was required to determine groat fraction, and no special laboratory facilities were needed. The trait should be especially useful in breeding programs where in vitro determinations are not possible or practical.

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